Which of the following correctly describes harmonics in electrical systems?

Harmonics in electrical systems refer to voltage or current waveforms that are multiples of the fundamental frequency (usually 50 or 60 Hz). While harmonics can have some beneficial aspects, such as improving the performance of certain types of equipment, they can also lead to significant issues, making the understanding of their effects crucial.

The correct explanation is that harmonics can cause issues such as overheating in electrical components. This occurs because harmonics can lead to increased current in conductors and transformers, resulting in excessive heating. Devices that are not designed to handle these higher frequencies can fail or operate inefficiently, potentially causing equipment damage and power quality issues.

In contrast, while some harmonics can potentially have positive effects in specific applications, they are not always beneficial across the board. The presence of harmonics can also influence power factor negatively, which adds more complexity to their impact on power systems. Lastly, stating that harmonics do not affect power systems overlooks the reality that they can significantly disrupt the normal operation and efficiency of electrical systems, manifesting as distortion in the voltage and current waveforms.